Bubble machine



FIG. 1 is a top perspective view of a bubble machine in accordance with our design;

FIG. 2 is a side elevation view of the bubble machine in accordance with our design, the opposite side being a mirror image of that shown;

FIG. 3 is a front elevation view of the bubble machine in accordance with our design;

FIG. 4 is a back elevation view of the bubble machine in accordance with our design;

FIG. 5 is a top plan view of the bubble machine in accordance with our design; and,

FIG. 6 is a bottom plan view of the bubble machine in accordance with our design.

The broken lines are included for the purpose of illustrating portions of the bubble machine that form no part of the claimed design. The appearance of the unshaded portions within the upper opening forms no part of the claimed design. 

The ornamental design for a bubble machine, as shown and described. 